Sand-grain core insecticidal composition



United States Patent O SAND-GRAIN CORE INSECTICIDAL COMPDSITION John F.Les Veaux, Middleport, and Edward F. Orwell, Medina, N. Y., assignors'to Food hiachinery and Chemical Corporation No Drawing. ApplicationOctober 1'6, 1952, Serial No. 315,188

6 Claims. (Cl. 167-42) The present invention rel-ates to tion coveredwith water.

In the large scale application of ing or dusting the insecticide, forplane or insecticides by sprayinstance from an airother airbornevehicle, considerable loss in insecticide is experienced by reasonwetted by the water. of the present invention to provide an which willnormally penetrate the insecticide as the active ingredient.

In accordance with the present invention, an impalpable powder carryingthe desired insecticide is prepared and distributed upon the surface ofa Water-insoluble core. In general, argillaceous materials, such as clayof the montmorillonite, kaolinite or other types of clay, is ground withthe insecticide in any desired ratio. In general, this ground materialwill be an 'impalpable powder, the fineness of which is such as todesignate it as a flourjthat is, on the order of 325 mesh or finer.

This mixture is then distributed upon the surface of a material as acore having a specific gravity greater than 1. The core material may beinsoluble in water. Windclassified beach sand, by reason of itscheapness and proper size, constitutes an excellent vehicle for the corematerial. The silica beach sand, argillaceous carrying material and theinsecticide may be blended together in an ordinary muller and theblending action is such as to produce a free-flowing product in whichthe individual grains of beach sand are not comminuted but are coatedwith a fine dust or film of dust which may be handled easily andsatisfactorily in conventional dusting devices employed in aerialdusting of areas. These coated grains, when falling in water-inundatedareas, such as swamps, rice fields, and the like, readily penetrate thesurface of the water and are carried to the bottom areas thereof wherethe argillaceous coating then is wetted; the insecticide carried in theclay and upon the core of the sand permeates the total area andeflfectively acts upon the larvae of insects, such as mosquitoes, whichnormally breed in such water-inundated areas. The efficiency of usage ofinsecticide applied in this manner is high, and, therefore, theapplication rate is low, since loss by wind dispersion is at a minimum,as is loss by attachment foliage since the pellets do not adhere tofoliage but will fall therethrongh into the water-inundated areas 'to betreated.

The pelletized material can .be made with any desired lnsectlclde, suchas BHC or 'b'enz-enehex'athat is,l,-2,3,4,10,1-0-hexachloroel,4,4a,5,sfiwhexachloro- 1,4,4a,5,8,8ahexahydro-1,4,5,8, dimethanonaphthalene and1,2,3,4,10,lO-hexachloro-(SJ-epoxy-l,4,4a,5,6,7,8,8al,4,5,8dimeth-anonaphthalene, respectively,

For the ordinary wind-classified portion by weight of sand wouldordinarily be in the of from about to about by weight of the finalproduct, and the coating about 20 to 5%. The composition of the coatingof the core of sand pellets about 20% to about 75% insecticide withbeach sand, the prothe coating composition comprised 42% of BHC(containing 36% of the gamma isomer) and 58% clay. Satisfactory killswere also obtained where the coating for the core of sand comprised 70%bentonite clay and 30% of BHC containing 36% of the gamma isomer.

A very satisfactory final product containing exceptional wetting anddispersing characteristics is possible of production by includingbentonite in any dusting clay in which the insecticide is to bedispersed. The characteristic swelling and gellification of thebentonite film of dust and dispersion would be 1.6 lbs. bentonite, 10.0lbs. sand 2060 mesh. These ingredients are introduced If it be foundnecessary to add the insecticide in the form of solution, a minimumamount of solvent should be employed to reduce subsequent dryingoperations to a minimum as the coating tends to be retained upon thesand particles and the finished product may be bagged, stored or shippedimmediately to the location of use, without fear of separation orsegregation of sand and clay.

What is claimed is:

1. An insecticidal composition in the form of a pellet comprising a coreof a grain of silica of 20 to 60 mesh and a coating upon said silicagrain of a finely ground argillaceous mineral powder not larger thanabout 325 mesh carrying an organic insecticide.

2. An insecticidal composition in the form of a pellet comprising a coreof a grain of silica of 20 to 60 mesh and a coating upon said silicagra-incomprising a finely ground argillaceons mineral powder not largerthan about 325 mesh and an organic insecticide.

3. The composition of claim 1 wherein the argillaceons mineral powder isbentonite clay.

4. Composition according to claim 1 wherein the insecticide is benzenehexachloride.

5. Composition according to claim 1 wherein the insecticide is DDT.

6. Composition according to claim 1 wherein the insecticide ischlordane.

'4 References Cited in the file of this patent UNITED STATES PATENTS1,450,128 Baker Mar. 27, 1923 5 2,330,227 Lynn Sept. 28, 1943 2,444,752Siegler July 6, 1948 2,506,635 Flenner May 9, 1950 pages 249 to

1. AN INSECTICIDAL COMPOSITION IN THE FORM OF A PELLET COMPRISING A COREOF A GRAIN OF SILICA OF 20 TO 60 MESH AND A COATING UPON SAID SILICAGRAIN OF A FINELY GROUND ARGILLACEOUS MINERAL POWDER NOT LARGER THANABOUT 325 MESH CARRYING AN ORGANIC INSECTICIDE.